Managing coal ash responsibly
Community interest in the way our industry manages coal combustion residuals continues to be high, as the Environmental Protection Agency considers new federal rules regulating coal-ash storage and disposal.
More than 90 percent of coal ash is made of the common elements found in soils, such as silicon, iron, aluminum and calcium. Less than 1 percent is composed of trace elements, such as arsenic, selenium or mercury, that also exist naturally in soils. Like any other industrial byproduct, coal ash must be managed properly.
Federal and state solid waste and water quality rules have governed coal-ash management for decades. Solid waste regulations dictate how the company handles, moves and stores the material, while water quality regulations protect surface water and groundwater.
State regulators evaluate ash basin discharges and issue permits that protect the health of lakes and rivers. In addition to limiting the release of compounds restricted by the permits, Duke Energy measures and reports the amounts of many other compounds. In addition, we have a long-standing dam safety program in place that involves ongoing maintenance and frequent inspections, including those conducted by state regulators.
Duke Energy scientists also monitor river and reservoir health as a whole, and report that data to regulators. In many cases, trace elements in the surface water are at or below the lowest levels laboratory instruments can accurately measure.
We also monitor groundwater around our ash basins and report that data to state regulators. If we were to find that our operations were affecting the quality of neighboring drinking water supplies, we would work closely with regulators to address and resolve the issue.
Duke Energy has invested tens of millions of dollars converting from fly-ash storage in ponds to dry fly-ash handling systems with disposal in lined landfills at nearly all of our large, scrubbed coal plants. These newer landfills are required to have synthetic liners, as well as drainage collection systems and groundwater monitoring wells.
And as we retire and decommission older coal plants over the next several years, we will close coal-ash basins in compliance with state and federal regulations. We will continue to monitor the groundwater around those basins and responsibly manage those sites for many years.